In air filtration systems requiring high efficiency filters such as High-Efficiency Particulate Air (HEPA) filters and other high efficiency filters, it is known to use some type of filter holding frame and a mechanical clamping mechanism to secure and effectively seal the filter to the holding frame. Such holding frames may be positioned within air ducts or filter housings of the air handling system. WO2012/134650 discloses a filter holding frame with an adjustable mechanical clamping mechanism including a frame having a downstream member coupled to a cross member, the downstream member and the cross member being adapted to fit within a housing. The frame assembly comprises at least two clamping mechanisms each coupled to a respective handle which is used to displace the frame assembly thereby clamping a filter unit received in a filter receiving aperture defined above the cross-member. When utilizing such mechanical clamping mechanisms to seal high efficiency filters, it is a requisite to ensure that any bypass or leakage around the seal is less than the maximum penetration of the filter.
Filter holding frames and clamping mechanisms as described above are typically used in critical filtration applications like for instance nuclear, pharmaceutical and risk laboratories. Very high safety standards complying with for instance increasingly stringent requirements from bio-safety authorities are thus applied. Periodic replacement of the filters is required to meet regulatory, and may involve the replacement of a large number of filters on a regular bases. A potential problem with clamping mechanism of the above type and others is that any mistake made during replacement of the filters in the air handling system, e.g. if the filters are not properly positioned, the clamping mechanism are not properly closed etc, could have devastating effects like causing a global pandemic.